On 03/02/2014 03:33 PM, Pádraig Brady wrote:
> On 03/02/2014 12:33 PM, Mateusz Jończyk wrote:
>> Hello,
>> There should be a warning when running df --si -h because it will display
>> results
>> in blocks of 1024 and not 1000, as one might think (the switch --si displays
>> blocks
>> in a human-readable format when used by itself).
>
> This is confusing.
Indeed, or not ...
> I think the confusion stems from the option names themselves.
> I.E. I'm not sure you'd want to warn as you might want to support overriding
> options.
> Consider: alias df='df -h'
>
> Then you could very well want to `df -H` to override the power from 1024 to
> 1000.
... because df really honors the last given option (as expected):
$ src/df -h / | sed 1d
/dev/sdb2 20G 8.7G 10G 47% /
$ src/df -H / | sed 1d
/dev/sdb2 22G 9.3G 11G 47% /
$ src/df -h -H / | sed 1d
/dev/sdb2 22G 9.3G 11G 47% /
$ src/df -H -h / | sed 1d
/dev/sdb2 20G 8.7G 10G 47% /
> So really the option should be --human-si not just --si.
Well, I'm 80:20 against this. Df(1) just honors the latest option
given - no matter what the name of the option's name is. Renaming
an option is almost always a "suboptimal" thing for users.
In this case, some might be already used to type "df --human" which
would not be distinguishable from --human-si anymore.
The problem is maybe that "df --help" doesn't explicitly say that -h
is using powers of 1024 no matter what other option was given before.
-h, --human-readable print sizes in human readable format (e.g., 1K 234M 2G)
-H, --si likewise, but use powers of 1000 not 1024
However, the info page is quite clear about this:
`-h'
`--human-readable'
Append a size letter to each size, such as `M' for mebibytes.
Powers of 1024 are used, not 1000; `M' stands for 1,048,576 bytes.
This option is equivalent to `--block-size=human-readable'. Use
the `--si' option if you prefer powers of 1000.
> Also I notice that in GNU df, -h and -H are 1024 and 1000 based respectively,
> whereas on FreeBSD it's the other way around :(
Outch. ;-(
Have a nice day,
Berny
